OpenClaw Context Window Fix | Generated by AI
Question: Why does OpenClaw show “Agent failed before reply: Model context window too small (8192 tokens). Minimum is 16000” and how to fix it?
Answer:
This error means the model you configured only supports an 8K context window, but OpenClaw’s agent requires at least 16K tokens to run. So the agent stops before replying.
Why this happens
- Your current model: 8,192 tokens max
- OpenClaw requirement: ≥ 16,000 tokens
- Result: agent refuses to start
This usually happens when using:
- small local GGUF models
- older Qwen / LLaMA configs
- wrong OpenRouter model variant
- llama.cpp server started with low context
Fix (choose one)
Fix 1 — Switch to a larger context model (recommended)
Use a model with 16K / 32K / 128K context.
Examples:
- DeepSeek-R1 (32K+)
- Qwen2.5-32B (32K)
- Mistral-Large (32K)
- Claude / GPT via OpenRouter (100K+)
For example (OpenClaw slash command):
/model openrouter/deepseek/deepseek-r1
or
/model openrouter/qwen/qwen-2.5-32b-instruct
Fix 2 — Increase llama.cpp context (local model)
If you’re running local server:
Start with larger context:
--ctx-size 16384
or better:
--ctx-size 32768
Example:
llama-server \
-m DeepSeek-R1.gguf \
--ctx-size 32768
Fix 3 — change OpenClaw agent requirement (not recommended)
You could lower requirement, but agent quality drops.
OpenClaw config:
agent:
min_context: 8192
But this often breaks:
- planning
- tool calling
- long code edits
So better upgrade model.
Quick diagnosis
Run:
openclaw model
or
openclaw doctor
You’ll likely see:
context: 8192
required: 16000
Best practical choice
Use:
/model llama-server/DeepSeek-R1-0528-Qwen3-8B-Q4_K_M.gguf
because it supports 32K context and works well with OpenClaw.
In short:
- error is normal
- your model too small
- switch to 16K+ model
- or increase ctx-size
That will immediately fix it.